Airdate: 10:30-11 p.m. Monday, June 16 (Showtime)

Related content: A few minutes with Billie Piper

 As projects go, "Secret Diary of a Call Girl" had an odder origin than most. That's probably why it is hardly the comedy that Showtime marketing suggests but more of a slice-of-life dramedy filled with the business of sex.

It started as a blog by someone, presumably a woman, named Belle. In the blog, Belle told about her experiences as a high-priced London call girl. She was poised, confident, well-educated and unapologetic about her work, which she kept entirely apart from her personal life.

The blog became a book, and the book became an eight-part series that ran on the BBC in the fall, which Showtime picked up to show here. In the process, the stories became more clinical and Belle became even more self-rigteous, neither of which moves the humor needle in the right direction.

Billie Piper, a familiar figure in the U.K. despite her tender years, stars as Belle. In the role, she spends more time breaking the fourth wall than breaking a sweat. Because the real Belle continues to remain anonymous, creator-writer Lucy Prebble had to invent a private life for the televised version. Here, Belle's real name is Hannah, she has one close friend (Iddo Goldberg), and she tells anyone who asks that she is a legal secretary.

Piper, who met the real Belle before production started, has the requisite sexiness and plays the role with near-reckless confidence. Don't stereotype me, she implores. She does not do drugs, was not sexually abused and has no children. She just likes the money and the hours.

Each episode features a specific type of client. There is the guy who hires her for a swinger party, the overnight client, the guy who's into S&M, the threesome and so on. One episode even covers the ramifications of getting bad online reviews.

It's eye-opening stuff, at least some of it, and yet not nearly as titillating as you might suppose. Considering the subject matter, there's surprisingly little nudity and practically nothing graphic. Softer than soft porn, "Call Girl" is as much a documentary about high-end prostitution as it is about the conflicts and foibles of those who engage in it.

Production: Tiger Aspect Prods. in association with Silverapples Media, IMG and ARG. Cast: Billie Piper, Cherie Lunghi, Iddo Goldberg. Executive producers: Greg Brenman, Avril Macrory, Michael Foster, Andrew Zein. Producer: Chrissy Skinns. Series producers: Rebecca De Souza, Roanna Benn. Line producer: Jacquie Glanville. Director: Yann Demange. Writer-creator: Lucy Prebble. Based on the blog: Belle du Jour: Diary of a London Call Girl. Director of photography: Tat Radcliffe. Production designer: Greg Shaw. Editor: Chris Wyatt; Set decorator: Alice Felton; Casting: Julia Duff.